IBD—with its two main clinical entities ulcerative colitis and Crohn's disease—is one of the most frequent gastrointestinal diseases in the developed world, placing a large burden on health-care services, and also has increasing incidence in developing countries. Although IBD is incurable, multiple drugs are available for the management of symptoms. IBD can develop rapidly in individuals of any age, from young children to older people in their sixties and seventies. Clinical research findings now indicate that the characteristics of the disease vary according to the age at disease onset and so specific management approaches are required depending on when IBD develops. This Focus issue brings together leaders in the field to provide new insights into the protection of mothers and babies during pregnancy and/or lactation, management of paediatric patients, how best to coordinate the transition of patients from a paediatrician to a gastroenterologist during adolescence, as well as how to diagnose and manage elderly-onset IBD.